Storage of track data in a position-controlled tilt system

ABSTRACT

A method and device for tilting a car body of a vehicle in a trackbound train when the train passes through a track curve. The respective vehicles in the train comprise bogies supporting a car body resting thereon, includes devices for tilting the car body in relation to the bogies, for indicating a track curve, and a control system for controlling the tilting of the car body in dependence on the geometry of the track curve. The position of the train along a route is determined point-by-point by the train being equipped with devices for detecting its position and by registering the curve geometry of the track when the train runs over a track section from the determined position, and storing it in real time as a sequence of measured values describing the curve geometry of the track section in an electronic memory. The curve-geometry data about the track section, previously stored in the memory is used for controlling the tilting of the car body during the next passage through curves within the track section.

TECHNICAL FIELD

The present invention relates to a method and a device for storage ofcurve-geometry track data for controlling the tilting of a car body of arailway vehicle when the vehicle passes through a track curve.

BACKGROUND OF THE INVENTION

It is known to increase the passenger comfort in a railway vehicle whenthe vehicle is running at a high speed through a track curve, by tiltingthe car body of the vehicle inwardly towards the curve while the vehicleis running through the track curve. In this way, the accelerationstresses on the passengers in the lateral direction are reduced, wherebythe vehicle may be driven at a higher speed through the track curvewhile maintaining passenger comfort in the vehicle. To achieve tiltingof the car bodies in the passenger vehicles which are part of aconnected train set, these vehicles are provided with specially arrangedcar tilting systems. This car tilting system achieves tilting of the carbodies in relation to the bogies of the vehicles, i.e. the wheelundercarriages, rotatable at least in the horizontal plane, in which thewheels and axles are mounted.

The control of the car body tilting in the respective vehicle in a trainset may be achieved in partially different ways. A common way is togenerate a control signal for the car body's tilting as a referencevalue, the basis of which is the acceleration in the lateral direction,which is measured by an accelerometer in the front bogie of the trainset (hereinafter referred to as the "lateral acceleration"). The lateralacceleration increases with the square of the speed of the train andproportionally to the curvature of the track curve (the inverse of thecurve radius). The tilting of the car body may, for example, becontrolled such that the tilting becomes substantially proportional tothe measured lateral acceleration, thus compensating for the whole, thelateral acceleration because of the tilting of the car body. In case offull compensation, the so-called compensation factor is said to be equalto 1.0; without tilt compensation the compensation factor is equal to 0.

The measured acceleration signal can be received by a computer (traincomputer) in the vehicle at the front of the train. The computercalculates a reference value of the tilting of the car body andtransmits the information (the reference value) on to the subsequentvehicles in the train in order for the car bodies of these vehicles totilt in proper order when the train set passes through the track curve.The reference values for the tilting which are thus received by eachvehicle are compared with the actual tilt angle (actual value) of eachvehicle body. A difference value between the reference value and theactual value for the tilting is passed, via regulator to a drive systemfor execution of a tilting of the car body which corresponds to thereference value. The drive system may, for example, consist of ahydraulic system with pressurized working cylinders which bring aboutthe forces required to tilt the car body in relation to the bogiessupporting the same. Also pneumatic or electric drive systems may beused.

Because of irregularities in the track and the dynamic movements of thebogie, the measured acceleration signal fluctuates. Before the measuredsignal from the accelerometer can be utilized to form a reference valuefor the car body tilt, it must be filtered. Otherwise, the tiltingmovement would become very irregular and jerky. However when filtering,the signal, is delayed. Depending, among other things, on how large theirregularities of the track are, this filtering and hence the delay maybe somewhat differently set for different operating cases. Certainadditional delays may occur in both the computer and the drive systemwhich executes the tilting movement.

The vehicle at the front of the train proceeds from a straight trackinto a transition curve, by which is meant a transitional part betweenthe straight and curved part of the curve, wherein the curvature of thecurve is successively and continuously changed. The first vehicle hastime to run a certain distance into the transition curve before thedelayed tilt signal is able to influence the tilting. The car body tiltof the front vehicle occurs somewhat too late in relation to the lateralacceleration caused by the speed of the train through the curve andwhich the tilting of the car body intends to completely, or at leastpartially compensate. The corresponding delay occurs also at the exitfrom the curve. A certain delay may in some cases also occur for thesecond vehicle in the train. The result of these delays may be that thepassengers in the front vehicles do not experience the satisfactorycomfort, despite the car body tilt. It may be experienced as disturbingfor the passengers, especially if the passengers are standing or walkingin the car. The problem is particularly noticeable when the leadingvehicle of the train is used for passengers.

Track curves not only have curvature in the horizontal plane, but alsonormally a rail superelevation. This means that the outer rail of thetrack is elevated above the inner rail for the purpose of compensatingfor the whole, or part of, the lateral acceleration to which the trainis subjected when negotiating curves, even with the tilting of the trainin the lateral direction.

At the same time, the curvature of the curve, and hence the lateralacceleration, changes when running through a transition curve, and therail superelevation in the curve also normally changes. The railsuperelevation is thereby given the shape of a ramp, along which thevertical position of the outer rail in relation to the inner rail iscontinuously changed. At different positions in the longitudinaldirection in such a rail superelevation ramp, the mutual verticalposition between the rails becomes different. Differences in the mutualvertical position between the rails are called track cross-level. Sincethe rail superelevation is normally changed at the same time as thecurvature of the curve and the lateral acceleration, the railsuperelevation ramp and the track cross-level coincide, with respect toposition and time, with the transition curve and with the increase oflateral acceleration.

Since the two bogies under a vehicle substantially on average incline tothe same extent as the track does, under the respective bogie,differences in the lateral inclination of the bogies will be readableapproximately at the same time as the lateral acceleration changes whenentering and leaving curves. Differences in the lateral inclination ofthe bogies can be measured with substantially vertically directedposition transducers between the car body and the bogie at each bogieside, provided that the car body is approximately a stiff body betweenthe two bogies. The rail superelevation ramp can also be indicated witha gyro which measures the angular velocity for the rotation of a bogiearound an axis in the direction of travel of the bogie. By adding ameasured signal for track cross-level or rail superelevation to thereference value formed by the lateral acceleration, but delayed, thetilt movement may be accelerated and the comfort improved.

Still, however, a certain delay of the reference value remains, whichresults in deteriorated comfort as compared with what would be the casewithout reference value delay. This is true at least for the leadingvehicle and, to some extent, possibly also for the second. Vehiclesfurther back in the train set will drive through the curve much laterthat the reference value signal, despite the delay, normally arrives intime to be able to effect timely and correct control of the car bodytilt.

To eliminate delay of the reference value which is otherwise unavoidablewhen running through a curve, at least in the leading vehicle, systemshave been tested wherein the train partly senses the position along thetrack, and partly uses stored, pre-determined ideal data for the curvegeometry in various curves along the track. In this way, correct tiltingmay be calculated in advance by a special calculating unit in thecontrol system for the car body tilt. This calculation is made as afunction of the position of the train, and its different vehicles, alongthe track. The disadvantage is that each train, which may be conceivedto run on a certain track section, must have current updated data aboutthe track geometry along the track section in question. The publicationsSE A, 8405046-7 (D1) and DE 3935740 (D2) describe examples of suchtechnique in which a train is provided with exchangeable data sequencesindicating the geometry of the track along a current track route. Amethod described in the above-mentioned publications entails anadministratively heavy system, wherein a railway authority is forcedconstantly to provide trains with updated memory modules with datasequences containing new curve data for each change of the curvegeometry along a route.

Another method presupposes the provision, in front of each curve, oreach group of curves, of a stationary signal transducer containingcurve-geometry data as a function of the position along the track afterthe signal transducer. The signal transducer is read by the train,during passage, and the information then obtained controls the car bodytilt system of the train. The disadvantage of such a system is that itis necessary to arrange a large number of signal transducers (onetransducer for each curve, or group of adjacent curves, in eachdirection of travel), and that the train may "miss" a transducer whichmay result in omission of the tilting of the car bodies of the train ina curve. Another disadvantage is that a signal transducer must beupdated each time a line change is carried out.

SUMMARY OF THE INVENTION

One object of the present invention is to eliminate the delay in thereference value signal which forms the basis of, and is used in, thecontrol system which controls the tilting of a car body in a vehicleincluded in a train when the train travels through a track curve. Toachieve this in a car body associated with a vehicle in a trackboundtrain when the train passes through a track curve, where the respectivevehicle in the train comprises bogies and a car body resting thereon,further means for tilting the car body in relation to these bogies, andmeans for indicating a track curve, and a control system for controllingthe car body's tilt in dependence on the track curve geometry, theposition of the train along the route is determined point-by-point bythe train being equipped with means for detecting the above-mentionedposition, by registering the curve geometry of the track when the traintravels over a track section from the determined position, and storingit on-line as a sequence of measured values describing the curvegeometry of the track section in an electronic memory, and by usingcurve-geometry data stored in the memory, about the track sectionderived from at least one journey which the train has made along thetrack section for controlling the car body tilt during passage of curveswithin the track section.

Data about the geometry of each curve track along a route are stored inthe train computer in a database in the form of sampled values for thetrack curvature and the rail superelevation angle for each track curve.These data have been formed by measurement and have initially dynamicdisturbances caused by the irregularities of the track. The disturbancesare eliminated or reduced by filtering, whereby data are given acertain, approximately known, delay in relation to the actual trackgeometry. In connection with storage and updating, track-geometry datafor the approximately known time delay are compensated. Stored dataabout the track curve, here called reference-value profile for the trackcurve (i.e. sampled values of the curvature and rail superelevation ofthe curve) are updated for each time the train passes through the sametrack curve.

By using stored data on the geometry of the track for the formation of asecond reference-value signal which substantially without delay controlsthe tilting of the car body, the tilting also of the first car and thesecond car in the train can be initiated without delay when the trainenters a track curve in dependence on the data about the geometry of thetrack curve. This is stored in the database in the train's computer fromthe preceding passage of the train or data from several precedingpassages through the same track curve. This increases the passengercomfort in the first and subsequent cars of the train when travellingthrough track curves at a high speed, which is an object of theinvention.

Another object of the invention is to eliminate the need of storingideal data, known in advance, about the track geometry for each tracksection, since track-geometry data for a route according to theinvention are continuously registered and stored, and changes in thetrack geometry are noted by the train computer in use for subsequenttravel by the train over the route. This eliminates a train's need forconstant access to data sequences with track-geometry data in some formof replaceable memory modules which have been provided with the latesttrack-geometry data about a route, for example according to the methoddescribed in publications D1 and D2.

Further, the train may be provided with transducers for forming a firstreference-value signal for control of the tilting of a car body in atraditional and known way in the form of an accelerometer for sensingthe lateral acceleration and transducers (gyros or position transducerssensing the track cross-level) for detecting the rail superelevationramp of the curve. This first type of reference-value formation ischosen if there are no stored track-geometry data in the database of thetrain (e.g. the first time a train runs along a certain route). It mayalso be chosen by the train personnel, during all of or parts of theroute, for example, if it is known that the track geometry has undergonemajor changes since last time the train run over and storedtrack-geometry data about all of or parts of the route in question.

The train is equipped with a position sensor, whereby the position ofthe train point-by-point may be determined by reading positiontransducers located along the route. The position transducer transmitsto the train computer information about the track section into which thetrain enters. The current position of the train within the track sectionis then calculated as a function of the train speed from the readposition on the line.

Position transducers along the route may comprise special signaltransducers, or be integrated with existing signal transducers,so-called transponders, along the track. The position indications mayinclude information about the route on which the train is running aswell as information as to where, along the line, the train is located.Alternatively, the train driver may indicate the route manually.

Another way of determining the position of the train along a route isgiven by the possibility of utilizing satellite navigation, GlobalPositioning System (GPS). By connecting a GPS receiver to the train'scomputer, the position of the train may be read continuously. In thisway, a track section along the track may be identified, for example, bythe position for the starting-point of the track section stored in thetrain computer, whereby the reference-value profile for thecorresponding track section may be read from the computer memory, and bewritten into the computer's memory, respectively, when the GPS receiverdetects a train position which coincides with the starting-point of thetrack section.

The first time a train passes over a certain route, the current curvegeometry is measured, processed, and stored in memory of a traincomputer which is part of the control system of the train. At the sametime, the information about the curve geometry in real time is usedimmediately for controlling the tilting system in the manner describedearlier, resulting in the disadvantage that a delay for tilting of atleast the first cars in the train occurs.

The geometry of a curve is determined by measuring two variables,namely, the course of the curvature of the curve, and the course of therail superelevation.

The curvature (ρ(s)=1/R(s)) of the curve, i.e., the inverse of the curveradius R(s), as a function of the longitudinal position (s) from thestarting-point (s=0) of a track section or the starting-point (s=0) of acurve is determined by measuring the angular velocity (dψ/dt) around avertical axis and dividing this angular velocity by the instantaneousoverall travel speed (v) ##EQU1##

The rail superelevation angle (φ(s)) of the curve as a function of thelongitudinal position (s) is determined by the time integral of theangular velocity (dφ/dt), measured around a longitudinal axis. That is,##EQU2##

The two angular velocities may be measured by gyros, suitably located inthe first bogie of the train. The disturbances effecting the signalsmust be filtered off, which provides signals with approximately knowndelays.

Sampled values of the curvature ρ and the rail superelevation angle φare stored online in the database of the train computer as an updatedreference-value profile for each track section of the covered route withthe given starting position of the track section as the starting-point,whereby the reference-value profile will contain the latestcurve-geometry data of each track section. Before being stored, sampledvalues are compensated for the approximately known time delay which isobtained during the filtering.

The car body tilt may, for example, be controlled to be proportional tothe lateral acceleration (a_(y)). The lateral acceleration is determinedapproximately by the following expressions, where g is the gravitationalacceleration ##EQU3##

The second, and subsequent times that the train runs over a certainroute, the previously measured and stored curve geometry for curveswithin a certain track section is used to calculate, and in advance, ina special calculating unit, correct reference values for tilting of thecar body for curves within the track section. This calculation is madeas a function of the position of the train, and of its various cars,along the track within the track section.

Since the delay in the stored signals is approximately known, this canbe taken into consideration in the calculation, and the tilting of thecar body of the respective vehicle may take place at the correct timefor all vehicles of the train.

The system receives a self-correcting function for changes incurve-geometry data, as from the running which takes place immediatelyafter the changed track-geometry data were measured and stored. Toreduce the dependence on accidental occurrences during an individualrunning, the mean value of the two or three immediately preceding storedreference-value profiles may alternatively be used.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying FIGURE schematically illustrates a diagram of thesystem which, according to the invention, achieves tilting of car bodiesin a train set.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A number of embodiments of the invention will be described withreference to the FIGURE.

When driving through a track curve, the lateral acceleration in theleading vehicle of the train is measured, usually at its front bogie bymeans of at least one accelerometer 1. The resulting signal is processedin a first signal processing unit 2. Thereafter, from the measuredacceleration value, the angle through which the car body of a vehicle,at full compensation for the lateral acceleration, is to tilt when thevehicle passes through the curve is calculated in a firstreference-value calculator 3. The calculated angular value is multipliedin the same unit by a compensation factor which possibly may vary withthe speed of the train through the curve, and a first reference-valuesignal is obtained. The train speed v is given by the speed transducer12, whose signal is passed to the first reference-value calculator 3.The reference-value signal is forwarded to the computers of thesubsequent vehicles together with information about a suitable delay forthe respective vehicle before tilting of the car body of the respectivevehicle is to be executed.

The delay for the respective vehicle is calculated in a calculator 4.The signal from the calculator 4 is passed to a regulator 5 which isprovided in the respective vehicle and which, by means of a controlsignal, controls the hydraulic and mechanical system 6 to effect thetilting of the car body 7 in accordance with the control signal. Thetilt angles of the car body 7 in relation to its two bogies, bogie A (8)and bogie B (9), respectively, is measured with a transducer at therespective bogie, whereafter the actual angular value for bogie A andbogie B, respectively, is passed to the regulator 5. The desired valuefor the tilt angle of the car body from the calculator 4 is compared inthe regulator with the mean value of the actual values for the tiltangles of the two bogies in relation to the car body. The difference,the so-called control error, is amplified and transformed to the currentsignal which controls the hydraulic and mechanical system 6, asmentioned above.

Because of the increased height of the outer rail in relation to theinner rail when entering a track curve, a rail superelevation may beindicated by measuring the difference between the tilt angles of thebogies in the same vehicle. According to the FIGURE, measured angles ofthe tilting of the respective bogie, and the speed of the train, arepassed to a second calculator 10 which generates a signal with asuperelevation contribution. This signal, with the superelevationcontribution, may be used for accelerating the formation of a referencevalue for the car body tilting. By adding this signal, thesuperelevation contribution, to a summator 11, the reference valuecalculation may be accelerated. As an alternative, a gyro may be usedfor the same purpose, to measure the angular velocity in the railsuperelevation ramp.

The embodiment of the car body tilt function which has been described sofar is part of the prior art. When using the reference-value calculationaccording to this method, a first reference-value signal is obtainedwith a delay τ than zero, as marked in the FIGURE.

According to the invention, the car body tilt system is supplemented bya second reference-value calculator 21. The second reference-valuecalculator 21 may be integrated with the train computer C, whichcomprises a memory M. A position sensor 13 registers the position n ofthe train at predetermined points along the route over which the trainis running. The predetermined points constitute starting points formutually unique track sections of the route. When the train is runningalong a given route, detection of a new starting-point for a new tracksection initiates storage into the memory M of a reference-value profilefor the new track section in a database, in which reference-valueprofiles for all track sections along the route are stored. Thereference-value profile consists of sampled values of a signal which isdependent on the curvature ρ of curves occurring within a track section,and of a signal which is dependent on the rail superelevation angle φ ofthese curves.

The curvature of a curve is measured with a first gyro 14 (rate gyroyaw). The angular velocity (dψ/dt) is measured around a vertical axis.After signal processing in a second signal processing unit 16,information about the angular velocity (dψ/dt) for the movement aroundthe vertical axis is passed to a calculating unit 18 in the computer C.In a corresponding way, the rail superelevation angle φ is measured witha second gyro 15 (rate gyro roll) which detects rotation by measurementof the angular velocity (dφ/dt) around a longitudinal axis (thelongitudinal axis for the bogie where the gyro is located). Also, thisangular velocity for the movement around the longitudinal axis is passedto the calculating unit 18, to which calculating unit 18 also there arefed the signals indicating the train speed v and the detected trainposition n. With the aid of the current train speed v, thestarting-point n of a train section, a clock pulse signal in thecomputer C, and the angular velocities dψ/dt and dφ/dt, there arecalculated in the calculating unit 18 sampled values in real time forcurvature and rail superelevation angle according to functions (1) and(2) above for a track section through which the train is temporarilyrunning. Each such sampled value is stored in a measured data memory 19,which will contain the latest version of curve-geometry data, that is,reference-value profiles, for all the track sections along the currentroute, when the train has covered the entire route. In connectiontherewith, compensation is made for the approximately known time delay.When the reference-value profiles of a whole route, here referred to asthe "route contour", have been stored into the measured data memory 19,these data may be dumped to a database 20 in the memory M, which storesat least the latest dumped route contour and preferably a series of thelatest stored route contours.

The reference-value profile of each track section consists of a sequenceof discrete measured values. For calculation in the secondreference-value calculator 21 of a lateral acceleration, based on thecourse of the curvature of the curve and the course of the railsuperelevation from reference-value profiles in the database 20 and bymeans of the train speed v, which is fed to the second reference-valuecalculator 21, formula (3) above is utilized.

In the second reference-value calculator 21 there may also be read, fromthe memory M (database 20), reference-value profiles from theimmediately preceding (consecutive) route contours with curve-geometrydata for the track section on which the train is currently running. Inthis connection, data from the latest route contour, or the mean valueof data from the latest consecutive route contours from the database 20,are used to form a reference value without delay (τ=0), which referencevalue is sent to an OR circuit 22 placed in the train computer C beforethe calculator 4 for calculating the delay of the car body tilt in thevarious vehicles of the train. This makes it possible to select in thecar body tilt system determination of the car body tilt either with areference value without delay (τ=0) or with delay (τ≠0), since also theinstantaneous, i.e., the first, reference-value signal measured inconventional manner is passed via the OR circuit 22 to the regulator 5of the car body tilt system.

The first reference-value signal may be selected by the OR circuit 22,for example if no track-geometry data for the current route are storedin the train database, or if the train personnel for some other reasonhave chosen to use the first reference-value formation.

As mentioned previously, the position sensor 13 receives informationabout the train position either via position transducers which aredisposed along the route and which are read by equipment on board thetrain, or via at least one receiver installed in the train for, forexample, satellite navigation according to the so-called GPS system.

The starting-point of a curve may also be stored with a known positionaccording to the GPS system into the train computer, whereby the traincomputer, via the GPS receiver, continuously seeks the starting positionof the next track section. When the expected position is attained, thetrain computer initiates storage and reading of the reference-valueprofile of the attained (identified) track section. In this connectionmay be mentioned that the reliability i.e. (accuracy) of such apositioning system increases with the use of increasingly moresatellites and to a still higher extent when the navigation signals aresupplemented with transmission from ground-based FM radio stations.

The hardware for calculating reference-value profiles consists ofconventional electronic units.

We claim:
 1. A method for tilting of a car body of a vehicle in atrackbound train when the train traverses a curved track, the respectivevehicle comprising bogies supporting a car body, means for tilting thecar body in relation to the bogies, means for indicating a track curve,and a control system for controlling the tilting of the car body independence on the geometry of the track curve, the method comprising thesteps of:determining the position of the train along a track route,point-by-point, by means for detecting its position provided on thetrain, registering the curve geometry data of the track when the traintraverses a track section from the determined position by means ofmembers for determining the curve geometry and storing the registereddata in real time as a sequence of measured values describing the curvegeometry of said track section in an electronic memory, and using atleast the latest sequence of curve-geometry measured values for thetrack section, stored in memory, for controlling the tilting of the carbody during the next passage of the train, in the same direction,through curves within the track section.
 2. A method according to claim1, further comprising storing in the memory consecutive sequences ofmeasured values registering curve geometry data from the consecutiverunning of the train in the same direction over the same track sectionand using a mean value of the curve-geometry data of the track sectionfrom at least two last stored consecutive sequences of measured valuesfor controlling the tilting of the car body during passage throughcurves within the track section.
 3. A method according to claim 1,further comprising using a sequence of measured values of curve-geometrydata for a track section from the preceding running of the train in thesame direction over said track section for controlling the tilting ofthe car body during passage through curves within the track section. 4.A method according to claim 1 wherein the position of the train alongthe route is determined point-by-point, by devices located on the trainfor reading position transducers placed along the route.
 5. A methodaccording to claim 1, wherein the position of the train is determined bythe devices on the train utilizing satellite navigation.
 6. Means forcontrolling tilting of at least one car body of a vehicle in atrackbound train when the train transverses a track curve, eachrespective vehicle in the train comprising bogies and a car body restingthereon, means for tilting the car body in relation to the bogies, meansfor indicating a track curve, and a control system for controlling thetilting of the car body in dependence on the geometry of the trackcurve, wherein the train is equipped with means for determining,point-by-point, the position of the train along a route, train bornedevices for determining the curve geometry of the track section from adetermined position by detecting a sequence of sampled measured valuesin real time of curve-geometry data for the track section when the trainruns over said track section, an electronic memory for storing saidsampled sequence of measured values of the curve geometry of the tracksection, and a second reference-value calculator responsive to at leastthe latest sequence of the curve-geometry measured values of the tracksection stored in the memory for calculating a reference value for thetilting of the car body in a vehicle in the train during the nextpassage of the train, in the same direction, through the curves withinthe track section.
 7. The controlling means according to claim 6,wherein said devices for determining the curve geometry includes meansfor detecting the curvature of track curve and means for detecting therail superelevation angle of the track curve.
 8. A device according toclaim 7, wherein the curvature of a track curve is detected by means ofa gyro.
 9. A device according to claim 7, wherein the railsuperelevation angle of a track curve is detected by means of a gyro.10. A device according to claim 6 wherein the train position determiningmeans include a position sensor located on the train for reading aposition transducer located along the route.
 11. A device according toclaim 6, wherein the train position determining means includes aposition sensor comprising a receiver for satellite navigation, and theposition of the train is read at predetermined points.
 12. A deviceaccording to claim 6, wherein the train position determining meansincludes a position sensor comprising a receiver for satellitenavigation and the position of the train is read at predeterminedintervals.
 13. A method for controlling a car body of a vehicle in atrackbound train passing through a track curve and wherein eachrespective vehicle in the train comprises bogies supporting a car bodythereon, said method comprising the steps of:a) determining the positionof the train along a route, point by point, by position detecting meansprovided on the train; b) registering the curve geometry of the trackdata when the train runs over a track section from the determinedposition; c) storing in an electronic memory the curve geometry data inreal time as a sequence of measured values describing the curve geometryof said track section; and d) controlling the tilting of the car bodyduring the next passage through curves within said track section byusing the previously stored curve geometry data of said track section.